The invention may be applied in buildings being provided to collect sewage but it can be also applied in other circumstances, for example in pits or in channels. The screening apparatus can be used overground, especially in case of the screening apparatus being included in a container. Buildings provided to collect sewage serve to store the sewage and to deliver the sewage with natural hydraulic gradient to the clarification plant. The liquid is lifted with a pump having a downstream conduit. The pump is arranged in a pump sump of the building. In such buildings, there often is little room to position the screening apparatus. The buildings in form of a pit have a certain depth and a small bottom area. In all of these cases, it is necessary to sieve the liquid containing floating and suspended debris, i.e. to set and to remove the debris so not to destroy the pump.
A screening apparatus is known from German Patent No. 44 12 679 C2. The separation area is fixedly connected to the oncoming tube and has a configuration of a housing. The screening apparatus is provided with a conveyor assembly to convey the debris upwardly. The conveyor assembly has a tube-like housing and a driven screw arranged therein. The conveyor assembly has a first horizontally arranged conveying section and a second vertically arranged conveying section. The sewage is sieved at the same time. The deposited debris is removed from the building. This combined sieving and conveying apparatus is fixedly arranged and connected to the oncoming tube, so that the liquid has to flow through the separating area. The separating area is cleaned over and over again by the revolving screw. Thus, there is no danger of debris loading or clogging the separation area. Consequently, the separation area can always fulfill its function. If the amount of debris to deposit increases more debris is deposited on the inner surface of the separation area, and more debris is conveyed upwardly out of the building. There are no periods in which the non-cleaned liquid can enter the pump. The separation area is part of the tube-like housing of the conveyor assembly. The conveyor assembly has a first horizontally arranged conveying section. The separation area is located in the first conveying section where the sieving takes place. The second vertically arranged conveying section serves to remove the deposited debris out of the building. The second conveying section can end in a discharge bend or a chute guiding the debris into a container. Arranging both of the conveying sections perpendicular to each other requires a great amount of room. The screw of the conveyor assembly can be driven continuously or discontinuously. It is possible to provide timely equal intervals to attain a certain partly loading or clogging of the separation area, and thus to use an increased filter effect. Nevertheless, there is the need of cleaning the separation area from time to time to prevent a complete loading or clogging of the separation area.